Ways to Compute a RichText field in lotus notes

When I try to compute a richtext field, I got these results which needs to be documented.

We can compute a richtext field in four ways.

We can see the four ways of computing the richtext field below.

Create a richtext field and make it as computed.

1. We can give formula for the richtext field.

2. We can leave the formula as blank(not "" or empty string. where as in text field, it throws an error while saving the form).

3. We can give any richtext field's name(may be its own name) instead of formula.

4. We can give any text field's name instead of formula.